The present invention relates to a yarn wetting apparatus, especially suitable for a two-for-one twisting spindle assembly, as well as a two-for-one twisting spindle assembly having such a yarn wetting apparatus disposed on an upper end of the hollow spindle axis thereof. A yarn wetting apparatus of this type includes a reservoir and a porous wetting body, which has a capillary capability and extends into the reservoir, and which includes a yarn intake opening which tapers to a relatively smaller diameter in the direction of the spindle hollow axis.
A two-for-one twisting spindle assembly or, respectively, a yarn wetting apparatus for a two-for-one twisting spindle assembly of this type, is described in DE 23 17 053 (equivalent to U.S. Pat. No. 3,864,901) and in DE 34 09 233 C1 (equivalent to U.S. Pat. No. 4,573,314).
An important component of a yarn wetting apparatus of this type is a porous wetting body, preferably comprised of a sinter material, which is partially immersed in the reservoir and which absorbs a wetting or lubricating agent directly from the reservoir and/or receives the wetting or lubricating agent supplementally via a wick system. In the operation of the two-for-one twisting spindle assembly, the yarn travels over the wetting body, preferably along a spherically shaped, inwardly tapering yarn passage opening and receives thereby the lubricating or wetting agent which has been delivered as a result of the capillary and suction action of the yarn wetting apparatus acting to draw the wetting agent from the reservoir to the surface of the wetting body over which the yarn travels in a manner such that a thin film of wetting agent or, respectively, a lubricating agent, is formed on the surface. If the yarn removes this film, the equilibrium in the wetting body capillary system is changed and new wetting agent or, respectively, lubricating agent, is transported to the surface. This process operates continuously.
Under certain operating conditions, it can occur that more wetting material is conducted to the wetting body surface over which the yarn travels than is taken up or received by the yarn. In this event, the danger arises that the excess or superfluous wetting agent can drip into the spindle hollow axis onto, for example, the yarn brakes which are disposed therein, which can thus lead to a disturbance of the operation.
As disclosed in DE 36 08 436 A1, in connection with a two-for-one twisting spindle assembly, the yarn wetting apparatus includes a two-portion porous wetting body. One portion comprises several wicks dipped into the reservoir and comprised of felt or another liquid absorbent material and which are disposed in the second wetting body portion which is itself comprised of a porous and firm polyolefin core and comprises a yarn passage opening which tapers inwardly in the yarn travel direction. The lower end of the yarn passage opening communicates into a substantially conical opening formed in a covering cap, which itself communicates with the yarn intake conduit of the two-for-one twisting spindle assembly such that this yarn wetting apparatus also operates to conduct without hindrance superfluous wetting agent into the yarn intake conduit and thereby into the thereto connected spindle hollow axis.
The present invention offers a solution to the challenge of providing a corresponding yarn wetting apparatus or a two-for-one twisting spindle assembly having a yarn wetting apparatus, respectively, which is so configured that the introduction of superfluous wetting agent into the region of the spindle hollow axis of the two-for-one twisting spindle assembly is prevented.
To provide a solution to this challenge, the inventive two-for-one twisting spindle assembly or, respectively, a corresponding yarn wetting apparatus regarded by itself, is characterized primarily in that the inner end of the yarn passage opening is in connection with the reservoir via at least one back flow channel for back flow therealong of a wetting agent to the reservoir.
In this manner, the superfluous wetting agent, which has not been taken up by the yarn, does not accumulate above the spindle hollow axis but, rather, is returned again directly to the reservoir.
The inner end of the yarn passage opening preferably has a greater diameter than that of the yarn intake opening of a yarn intake conduit which extends along an extension of the spindle hollow axis, the upper end of which is encircled by a receipt chamber for superfluous wetting agent, whereby the receipt chamber is in communication, via one or several back flow channels, with the reservoir.
In connection with the system described in DE 34 09 239 C1, with particular emphasis on FIG. 2 thereof, in which the yarn wetting apparatus comprises a nipple extending through the reservoir and communicated with the spindle hollow axis and on which a portion of the wetting body projecting into the reservoir has been inserted, there is, in a further modification of the apparatus of the present invention, a back flow channel between the outer wall of the nipple and the inner wall of the wetting body portion which projects into the reservoir.
The object and advantages of the present invention will appear more clearly from the following specification in conjunction with the accompanying schematic drawing, in which:
The sole FIGURE of the drawing shows the preferred embodiment of the yarn wetting apparatus in sectional view on an upper end of the spindle hollow axis of a two-for-one twisting spindle assembly.